Effects of GnRH vaccination in wild and captive African Elephant bulls (Loxodonta africana) on reproductive organs and semen quality

OBJECTIVES: Although the African elephant (Loxodonta africana) is classified as endangered by the International Union for Conservation of Nature (IUCN), in some isolated habitats in southern Africa, contraception is of major interest due to local overpopulation. GnRH vaccination has been promoted as a non-invasive contraceptive measure for population management of overabundant wildlife. We tested the efficacy of this treatment for fertility control in elephant bulls. METHODS: In total, 17 male African elephants that were treated with a GnRH vaccine were examined in two groups. In the prospective study group 1 (n = 11 bulls, ages: 8±36 years), semen quality, the testes, seminal vesicles, ampullae and prostate, which were all measured by means of transrectal ultrasound, and faecal androgen metabolite concentrations were monitored over a three-year period. Each bull in the prospective study received 5 ml of Improvac® (1000 μg GnRH conjugate) intramuscularly after the first examination, followed by a booster six weeks later and thereafter every 5±7 months. In a retrospective study group (group 2, n = 6, ages: 19±33 years), one examination was performed on bulls which had been treated with GnRH vaccine for 5±11 years. RESULTS: In all bulls of group 1, testicular and accessory sex gland sizes decreased significantly after the third vaccination. In six males examined prior to vaccination and again after more than five vaccinations, the testis size was reduced by 57.5%. Mean testicular height and length decreased from 13.3 ± 2.6 cm x 15.2 ± 2.8 cm at the beginning to 7.6 ± 2.1 cm x 10.2 ± 1.8 cm at the end of the study. Post pubertal bulls (>9 years, n = 6) examined prior to vaccination produced ejaculates with viable spermatozoa (volume: 8±175 ml, sperm concentration: 410-4000x106/ml, total motility: 0±90%), while after 5±8 injections, only 50% of these bulls produced ejaculates with a small number of immotile spermatozoa. The ejaculates of group 2 bulls (vaccinated >8 times) were devoid of spermatozoa. Faecal androgen metabolite concentrations measured in captive males decreased significantly after the fourth vaccination. None of the males entered musth during the treatment period. CONCLUSIONS: Our results showed a marked decrease in semen quality, testicle and secondary sex gland sizes following repeated GnRH vaccinations. After 2±4 years of continuous treatment every 5±7 months, the effects were similar to surgical castration.ISIScopu

Investigation of Interferon stimulated genes (ISGs) simultaneously in endometrium, corpus luteum (CL) and peripheral blood mononuclear cells (PBMCs) in early pregnant ewes

19th Annual Conference of the European-Society-for-Domestic-Animal-Reproduction (ESDAR) -- SEP 17-19, 2015 -- Albena, BULGARIAWOS: 000364593400126European Soc Domest Anim Repro

Effect of lavender (Lavandula Stoechas) essential oil on growth performance, carcass characteristics, meat quality and antioxidant status of broilers

The study evaluated the effect of essential oils from lavender (Lavandula stoaches) (LEO), on growth performance, carcass quality and antioxidant status of broilers. Three nutritionally adequate diets were composed with the addition of LEO at 0, 24, and 48 mg/kg of feed. The diets were fed as mash in the starter (d 0-21) and grower (d 22-39) phases. A total of 405 day-old chicks (Ross-308) were allocated to the three dietary treatments, each with three replicate pens with 45 birds per pen. After the first 21-day feeding period, the bodyweight of chicks fed 24 mg/kg LEO was higher (P <0.01) than the 48 mg/kg LEO treatment, but only slightly higher than that of the untreated group. Diets with 24 and 48 mg/kg of LEO tended to increase final bodyweight of birds at 39 days old. No differences were observed for feed intake (FI), feed conversion ratio (FCR) and mortality among treatments. Feeding chickens on a diet with added LEO significantly reduced the relative weight of liver (P <0.01) compared with the control (CNT) group. Percentage of spleen weight of birds fed 24 mg/kg LEO was lower (P <0.05) than for those who received 48 mg/kg LEO. However, it was similar to that of the CNT. Birds fed diets supplemented with 24 and 48 mg/kg LEO had breast meat with higher brightness (L* value) and higher concentration of superoxide dismutase (SOD) compared with birds that did not receive LEO. Based on the data, it can be concluded that LEO could be used as a growth promoter in broiler nutrition with potential improvements in breast meat quality

Effect of lavender (<i>Lavandula Stoechas</i>) essential oil on growth performance, carcass characteristics, meat quality and antioxidant status of broilers

The study evaluated the effect of essential oils from lavender (Lavandula stoaches) (LEO), on growth performance, carcass quality and antioxidant status of broilers. Three nutritionally adequate diets were composed with the addition of LEO at 0, 24, and 48 mg/kg of feed. The diets were fed as mash in the starter (d 0-21) and grower (d 22-39) phases. A total of 405 day-old chicks (Ross-308) were allocated to the three dietary treatments, each with three replicate pens with 45 birds per pen. After the first 21-day feeding period, the bodyweight of chicks fed 24 mg/kg LEO was higher (P <0.01) than the 48 mg/kg LEO treatment, but only slightly higher than that of the untreated group. Diets with 24 and 48 mg/kg of LEO tended to increase final bodyweight of birds at 39 days old. No differences were observed for feed intake (FI), feed conversion ratio (FCR) and mortality among treatments. Feeding chickens on a diet with added LEO significantly reduced the relative weight of liver (P <0.01) compared with the control (CNT) group. Percentage of spleen weight of birds fed 24 mg/kg LEO was lower (P <0.05) than for those who received 48 mg/kg LEO. However, it was similar to that of the CNT. Birds fed diets supplemented with 24 and 48 mg/kg LEO had breast meat with higher brightness (L* value) and higher concentration of superoxide dismutase (SOD) compared with birds that did not receive LEO. Based on the data, it can be concluded that LEO could be used as a growth promoter in broiler nutrition with potential improvements in breast meat quality

Evaluation of immunocastration conjugates based on GnRH linked to carrier molecules in a male rodent model

Gonadotropin-releasing hormone (GnRH) stimulates the pituitary gland to secrete sex hormones. In the present study, we evaluated different conjugates of GnRH to abrogate sex hormone secretion in a male rat model. Firstly, GnRH-I was conjugated to keyhole limpet haemocyanin (KLH) using either whole-sequence GnRH-I or an analogue of GnRH-I (CHWSYGLRPG-NH2) using glutaraldehyde cross linkage. Six-week-old Sprague-Dawley male rats (n=6) were immunized intramuscularly with the conjugates adsorbed onto alum, equivalent to 50 μg of GnRH peptide and administered in weeks 1, 3, 5 and 7. The study was concluded in week 15. Comparison was made with untreated controls and previously established anti-fertility conjugates: CHWSYGLRPG-NH2 (GnRH-I) or CHWSHDWKPG-NH2 (analogue of lamprey GnRH-III, lGnRH-III) linked to tetanus toxoid (using a heterobifunctional reagent to achieve cross linkage). Antibody production, hormone levels and testicular diameter changes were assessed, together with, sperm movement and effects on organ weights. Similar high levels of antibody secretion were observed in all the immunized groups, although whole GnRHI- KLH produced a sustained level of production for an additional week. Similarly, testosterone levels were significantly (p<0.05) reduced in all immunized groups. There were no significant changes observed in body weight and testicular diameter of immunized animals compared with the untreated controls. However, in terms of sperm motility and sperm number, the best anti-fertility effects were observed with lGnRH-III-TT and GnRH-I-KLH and to a lesser extent whole GnRH-I-KLH. These groups also showed significant increase in kidney weight. Finally, considering all the above-mentioned subjects in addition to availability and easier and cheaper way of preparation,we came to this conclusion that whole GnRH-IKLH satisfactorily met most of our favourite criteria and could be used in immunocastration vaccine production purposes successfully